1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
3 * (C) 2007 Patrick McHardy <kaber@trash.net>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 */
9
10 #include <linux/types.h>
11 #include <linux/timer.h>
12 #include <linux/module.h>
13 #include <linux/udp.h>
14 #include <linux/seq_file.h>
15 #include <linux/skbuff.h>
16 #include <linux/ipv6.h>
17 #include <net/ip6_checksum.h>
18 #include <net/checksum.h>
19
20 #include <linux/netfilter.h>
21 #include <linux/netfilter_ipv4.h>
22 #include <linux/netfilter_ipv6.h>
23 #include <net/netfilter/nf_conntrack_l4proto.h>
24 #include <net/netfilter/nf_conntrack_ecache.h>
25 #include <net/netfilter/nf_log.h>
26
27 static unsigned int nf_ct_udplite_timeout __read_mostly = 30*HZ;
28 static unsigned int nf_ct_udplite_timeout_stream __read_mostly = 180*HZ;
29
30 static int udplite_pkt_to_tuple(const struct sk_buff *skb,
31 unsigned int dataoff,
32 struct nf_conntrack_tuple *tuple)
33 {
34 const struct udphdr *hp;
35 struct udphdr _hdr;
36
37 hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
38 if (hp == NULL)
39 return 0;
40
41 tuple->src.u.udp.port = hp->source;
42 tuple->dst.u.udp.port = hp->dest;
43 return 1;
44 }
45
46 static int udplite_invert_tuple(struct nf_conntrack_tuple *tuple,
47 const struct nf_conntrack_tuple *orig)
48 {
49 tuple->src.u.udp.port = orig->dst.u.udp.port;
50 tuple->dst.u.udp.port = orig->src.u.udp.port;
51 return 1;
52 }
53
54 /* Print out the per-protocol part of the tuple. */
55 static int udplite_print_tuple(struct seq_file *s,
56 const struct nf_conntrack_tuple *tuple)
57 {
58 return seq_printf(s, "sport=%hu dport=%hu ",
59 ntohs(tuple->src.u.udp.port),
60 ntohs(tuple->dst.u.udp.port));
61 }
62
63 /* Returns verdict for packet, and may modify conntracktype */
64 static int udplite_packet(struct nf_conn *ct,
65 const struct sk_buff *skb,
66 unsigned int dataoff,
67 enum ip_conntrack_info ctinfo,
68 int pf,
69 unsigned int hooknum)
70 {
71 /* If we've seen traffic both ways, this is some kind of UDP
72 stream. Extend timeout. */
73 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
74 nf_ct_refresh_acct(ct, ctinfo, skb,
75 nf_ct_udplite_timeout_stream);
76 /* Also, more likely to be important, and not a probe */
77 if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
78 nf_conntrack_event_cache(IPCT_STATUS, skb);
79 } else
80 nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_udplite_timeout);
81
82 return NF_ACCEPT;
83 }
84
85 /* Called when a new connection for this protocol found. */
86 static int udplite_new(struct nf_conn *ct, const struct sk_buff *skb,
87 unsigned int dataoff)
88 {
89 return 1;
90 }
91
92 static int udplite_error(struct sk_buff *skb, unsigned int dataoff,
93 enum ip_conntrack_info *ctinfo,
94 int pf,
95 unsigned int hooknum)
96 {
97 unsigned int udplen = skb->len - dataoff;
98 const struct udphdr *hdr;
99 struct udphdr _hdr;
100 unsigned int cscov;
101
102 /* Header is too small? */
103 hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
104 if (hdr == NULL) {
105 if (LOG_INVALID(IPPROTO_UDPLITE))
106 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
107 "nf_ct_udplite: short packet ");
108 return -NF_ACCEPT;
109 }
110
111 cscov = ntohs(hdr->len);
112 if (cscov == 0)
113 cscov = udplen;
114 else if (cscov < sizeof(*hdr) || cscov > udplen) {
115 if (LOG_INVALID(IPPROTO_UDPLITE))
116 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
117 "nf_ct_udplite: invalid checksum coverage ");
118 return -NF_ACCEPT;
119 }
120
121 /* UDPLITE mandates checksums */
122 if (!hdr->check) {
123 if (LOG_INVALID(IPPROTO_UDPLITE))
124 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
125 "nf_ct_udplite: checksum missing ");
126 return -NF_ACCEPT;
127 }
128
129 /* Checksum invalid? Ignore. */
130 if (nf_conntrack_checksum && !skb_csum_unnecessary(skb) &&
131 hooknum == NF_INET_PRE_ROUTING) {
132 if (pf == PF_INET) {
133 struct iphdr *iph = ip_hdr(skb);
134
135 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
136 udplen, IPPROTO_UDPLITE, 0);
137 } else {
138 struct ipv6hdr *ipv6h = ipv6_hdr(skb);
139 __wsum hsum = skb_checksum(skb, 0, dataoff, 0);
140
141 skb->csum = ~csum_unfold(
142 csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
143 udplen, IPPROTO_UDPLITE,
144 csum_sub(0, hsum)));
145 }
146
147 skb->ip_summed = CHECKSUM_NONE;
148 if (__skb_checksum_complete_head(skb, dataoff + cscov)) {
149 if (LOG_INVALID(IPPROTO_UDPLITE))
150 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
151 "nf_ct_udplite: bad UDPLite "
152 "checksum ");
153 return -NF_ACCEPT;
154 }
155 skb->ip_summed = CHECKSUM_UNNECESSARY;
156 }
157
158 return NF_ACCEPT;
159 }
160
161 #ifdef CONFIG_SYSCTL
162 static unsigned int udplite_sysctl_table_users;
163 static struct ctl_table_header *udplite_sysctl_header;
164 static struct ctl_table udplite_sysctl_table[] = {
165 {
166 .ctl_name = CTL_UNNUMBERED,
167 .procname = "nf_conntrack_udplite_timeout",
168 .data = &nf_ct_udplite_timeout,
169 .maxlen = sizeof(unsigned int),
170 .mode = 0644,
171 .proc_handler = &proc_dointvec_jiffies,
172 },
173 {
174 .ctl_name = CTL_UNNUMBERED,
175 .procname = "nf_conntrack_udplite_timeout_stream",
176 .data = &nf_ct_udplite_timeout_stream,
177 .maxlen = sizeof(unsigned int),
178 .mode = 0644,
179 .proc_handler = &proc_dointvec_jiffies,
180 },
181 {
182 .ctl_name = 0
183 }
184 };
185 #endif /* CONFIG_SYSCTL */
186
187 static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite4 __read_mostly =
188 {
189 .l3proto = PF_INET,
190 .l4proto = IPPROTO_UDPLITE,
191 .name = "udplite",
192 .pkt_to_tuple = udplite_pkt_to_tuple,
193 .invert_tuple = udplite_invert_tuple,
194 .print_tuple = udplite_print_tuple,
195 .packet = udplite_packet,
196 .new = udplite_new,
197 .error = udplite_error,
198 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
199 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
200 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
201 .nla_policy = nf_ct_port_nla_policy,
202 #endif
203 #ifdef CONFIG_SYSCTL
204 .ctl_table_users = &udplite_sysctl_table_users,
205 .ctl_table_header = &udplite_sysctl_header,
206 .ctl_table = udplite_sysctl_table,
207 #endif
208 };
209
210 static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite6 __read_mostly =
211 {
212 .l3proto = PF_INET6,
213 .l4proto = IPPROTO_UDPLITE,
214 .name = "udplite",
215 .pkt_to_tuple = udplite_pkt_to_tuple,
216 .invert_tuple = udplite_invert_tuple,
217 .print_tuple = udplite_print_tuple,
218 .packet = udplite_packet,
219 .new = udplite_new,
220 .error = udplite_error,
221 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
222 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
223 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
224 .nla_policy = nf_ct_port_nla_policy,
225 #endif
226 #ifdef CONFIG_SYSCTL
227 .ctl_table_users = &udplite_sysctl_table_users,
228 .ctl_table_header = &udplite_sysctl_header,
229 .ctl_table = udplite_sysctl_table,
230 #endif
231 };
232
233 static int __init nf_conntrack_proto_udplite_init(void)
234 {
235 int err;
236
237 err = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udplite4);
238 if (err < 0)
239 goto err1;
240 err = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udplite6);
241 if (err < 0)
242 goto err2;
243 return 0;
244 err2:
245 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
246 err1:
247 return err;
248 }
249
250 static void __exit nf_conntrack_proto_udplite_exit(void)
251 {
252 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite6);
253 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
254 }
255
256 module_init(nf_conntrack_proto_udplite_init);
257 module_exit(nf_conntrack_proto_udplite_exit);
258
259 MODULE_LICENSE("GPL");
260
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